2 * Register cache access API - rbtree caching support
4 * Copyright 2011 Wolfson Microelectronics plc
6 * Author: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
13 #include <linux/slab.h>
14 #include <linux/device.h>
15 #include <linux/debugfs.h>
16 #include <linux/rbtree.h>
17 #include <linux/seq_file.h>
21 static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
23 static int regcache_rbtree_exit(struct regmap *map);
25 struct regcache_rbtree_node {
26 /* the actual rbtree node holding this block */
28 /* base register handled by this block */
29 unsigned int base_reg;
30 /* block of adjacent registers */
32 /* number of registers available in the block */
34 } __attribute__ ((packed));
36 struct regcache_rbtree_ctx {
38 struct regcache_rbtree_node *cached_rbnode;
41 static inline void regcache_rbtree_get_base_top_reg(
43 struct regcache_rbtree_node *rbnode,
44 unsigned int *base, unsigned int *top)
46 *base = rbnode->base_reg;
47 *top = rbnode->base_reg + ((rbnode->blklen - 1) * map->reg_stride);
50 static unsigned int regcache_rbtree_get_register(
51 struct regcache_rbtree_node *rbnode, unsigned int idx,
52 unsigned int word_size)
54 return regcache_get_val(rbnode->block, idx, word_size);
57 static void regcache_rbtree_set_register(struct regcache_rbtree_node *rbnode,
58 unsigned int idx, unsigned int val,
59 unsigned int word_size)
61 regcache_set_val(rbnode->block, idx, val, word_size);
64 static struct regcache_rbtree_node *regcache_rbtree_lookup(struct regmap *map,
67 struct regcache_rbtree_ctx *rbtree_ctx = map->cache;
69 struct regcache_rbtree_node *rbnode;
70 unsigned int base_reg, top_reg;
72 rbnode = rbtree_ctx->cached_rbnode;
74 regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg,
76 if (reg >= base_reg && reg <= top_reg)
80 node = rbtree_ctx->root.rb_node;
82 rbnode = container_of(node, struct regcache_rbtree_node, node);
83 regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg,
85 if (reg >= base_reg && reg <= top_reg) {
86 rbtree_ctx->cached_rbnode = rbnode;
88 } else if (reg > top_reg) {
89 node = node->rb_right;
90 } else if (reg < base_reg) {
98 static int regcache_rbtree_insert(struct regmap *map, struct rb_root *root,
99 struct regcache_rbtree_node *rbnode)
101 struct rb_node **new, *parent;
102 struct regcache_rbtree_node *rbnode_tmp;
103 unsigned int base_reg_tmp, top_reg_tmp;
104 unsigned int base_reg;
107 new = &root->rb_node;
109 rbnode_tmp = container_of(*new, struct regcache_rbtree_node,
111 /* base and top registers of the current rbnode */
112 regcache_rbtree_get_base_top_reg(map, rbnode_tmp, &base_reg_tmp,
114 /* base register of the rbnode to be added */
115 base_reg = rbnode->base_reg;
117 /* if this register has already been inserted, just return */
118 if (base_reg >= base_reg_tmp &&
119 base_reg <= top_reg_tmp)
121 else if (base_reg > top_reg_tmp)
122 new = &((*new)->rb_right);
123 else if (base_reg < base_reg_tmp)
124 new = &((*new)->rb_left);
127 /* insert the node into the rbtree */
128 rb_link_node(&rbnode->node, parent, new);
129 rb_insert_color(&rbnode->node, root);
134 #ifdef CONFIG_DEBUG_FS
135 static int rbtree_show(struct seq_file *s, void *ignored)
137 struct regmap *map = s->private;
138 struct regcache_rbtree_ctx *rbtree_ctx = map->cache;
139 struct regcache_rbtree_node *n;
140 struct rb_node *node;
141 unsigned int base, top;
144 int this_registers, average;
148 for (node = rb_first(&rbtree_ctx->root); node != NULL;
149 node = rb_next(node)) {
150 n = container_of(node, struct regcache_rbtree_node, node);
152 regcache_rbtree_get_base_top_reg(map, n, &base, &top);
153 this_registers = ((top - base) / map->reg_stride) + 1;
154 seq_printf(s, "%x-%x (%d)\n", base, top, this_registers);
157 registers += this_registers;
161 average = registers / nodes;
165 seq_printf(s, "%d nodes, %d registers, average %d registers\n",
166 nodes, registers, average);
173 static int rbtree_open(struct inode *inode, struct file *file)
175 return single_open(file, rbtree_show, inode->i_private);
178 static const struct file_operations rbtree_fops = {
182 .release = single_release,
185 static void rbtree_debugfs_init(struct regmap *map)
187 debugfs_create_file("rbtree", 0400, map->debugfs, map, &rbtree_fops);
190 static void rbtree_debugfs_init(struct regmap *map)
195 static int regcache_rbtree_init(struct regmap *map)
197 struct regcache_rbtree_ctx *rbtree_ctx;
201 map->cache = kmalloc(sizeof *rbtree_ctx, GFP_KERNEL);
205 rbtree_ctx = map->cache;
206 rbtree_ctx->root = RB_ROOT;
207 rbtree_ctx->cached_rbnode = NULL;
209 for (i = 0; i < map->num_reg_defaults; i++) {
210 ret = regcache_rbtree_write(map,
211 map->reg_defaults[i].reg,
212 map->reg_defaults[i].def);
217 rbtree_debugfs_init(map);
222 regcache_rbtree_exit(map);
226 static int regcache_rbtree_exit(struct regmap *map)
228 struct rb_node *next;
229 struct regcache_rbtree_ctx *rbtree_ctx;
230 struct regcache_rbtree_node *rbtree_node;
232 /* if we've already been called then just return */
233 rbtree_ctx = map->cache;
237 /* free up the rbtree */
238 next = rb_first(&rbtree_ctx->root);
240 rbtree_node = rb_entry(next, struct regcache_rbtree_node, node);
241 next = rb_next(&rbtree_node->node);
242 rb_erase(&rbtree_node->node, &rbtree_ctx->root);
243 kfree(rbtree_node->block);
247 /* release the resources */
254 static int regcache_rbtree_read(struct regmap *map,
255 unsigned int reg, unsigned int *value)
257 struct regcache_rbtree_node *rbnode;
258 unsigned int reg_tmp;
260 rbnode = regcache_rbtree_lookup(map, reg);
262 reg_tmp = (reg - rbnode->base_reg) / map->reg_stride;
263 *value = regcache_rbtree_get_register(rbnode, reg_tmp,
264 map->cache_word_size);
273 static int regcache_rbtree_insert_to_block(struct regcache_rbtree_node *rbnode,
274 unsigned int pos, unsigned int reg,
275 unsigned int value, unsigned int word_size)
279 blk = krealloc(rbnode->block,
280 (rbnode->blklen + 1) * word_size, GFP_KERNEL);
284 /* insert the register value in the correct place in the rbnode block */
285 memmove(blk + (pos + 1) * word_size,
286 blk + pos * word_size,
287 (rbnode->blklen - pos) * word_size);
289 /* update the rbnode block, its size and the base register */
293 rbnode->base_reg = reg;
295 regcache_rbtree_set_register(rbnode, pos, value, word_size);
299 static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
302 struct regcache_rbtree_ctx *rbtree_ctx;
303 struct regcache_rbtree_node *rbnode, *rbnode_tmp;
304 struct rb_node *node;
306 unsigned int reg_tmp;
311 rbtree_ctx = map->cache;
312 /* if we can't locate it in the cached rbnode we'll have
313 * to traverse the rbtree looking for it.
315 rbnode = regcache_rbtree_lookup(map, reg);
317 reg_tmp = (reg - rbnode->base_reg) / map->reg_stride;
318 val = regcache_rbtree_get_register(rbnode, reg_tmp,
319 map->cache_word_size);
322 regcache_rbtree_set_register(rbnode, reg_tmp, value,
323 map->cache_word_size);
325 /* look for an adjacent register to the one we are about to add */
326 for (node = rb_first(&rbtree_ctx->root); node;
327 node = rb_next(node)) {
328 rbnode_tmp = rb_entry(node, struct regcache_rbtree_node,
330 for (i = 0; i < rbnode_tmp->blklen; i++) {
331 reg_tmp = rbnode_tmp->base_reg +
332 (i * map->reg_stride);
333 if (abs(reg_tmp - reg) != map->reg_stride)
335 /* decide where in the block to place our register */
336 if (reg_tmp + map->reg_stride == reg)
340 ret = regcache_rbtree_insert_to_block(rbnode_tmp, pos,
342 map->cache_word_size);
345 rbtree_ctx->cached_rbnode = rbnode_tmp;
349 /* we did not manage to find a place to insert it in an existing
350 * block so create a new rbnode with a single register in its block.
351 * This block will get populated further if any other adjacent
352 * registers get modified in the future.
354 rbnode = kzalloc(sizeof *rbnode, GFP_KERNEL);
358 rbnode->base_reg = reg;
359 rbnode->block = kmalloc(rbnode->blklen * map->cache_word_size,
361 if (!rbnode->block) {
365 regcache_rbtree_set_register(rbnode, 0, value, map->cache_word_size);
366 regcache_rbtree_insert(map, &rbtree_ctx->root, rbnode);
367 rbtree_ctx->cached_rbnode = rbnode;
373 static int regcache_rbtree_sync(struct regmap *map, unsigned int min,
376 struct regcache_rbtree_ctx *rbtree_ctx;
377 struct rb_node *node;
378 struct regcache_rbtree_node *rbnode;
384 rbtree_ctx = map->cache;
385 for (node = rb_first(&rbtree_ctx->root); node; node = rb_next(node)) {
386 rbnode = rb_entry(node, struct regcache_rbtree_node, node);
388 if (rbnode->base_reg < min)
390 if (rbnode->base_reg > max)
392 if (rbnode->base_reg + rbnode->blklen < min)
395 if (min > rbnode->base_reg)
396 base = min - rbnode->base_reg;
400 if (max < rbnode->base_reg + rbnode->blklen)
401 end = max - rbnode->base_reg + 1;
403 end = rbnode->blklen;
405 for (i = base; i < end; i++) {
406 regtmp = rbnode->base_reg + (i * map->reg_stride);
407 val = regcache_rbtree_get_register(rbnode, i,
408 map->cache_word_size);
410 /* Is this the hardware default? If so skip. */
411 ret = regcache_lookup_reg(map, regtmp);
412 if (ret >= 0 && val == map->reg_defaults[ret].def)
415 map->cache_bypass = 1;
416 ret = _regmap_write(map, regtmp, val);
417 map->cache_bypass = 0;
420 dev_dbg(map->dev, "Synced register %#x, value %#x\n",
428 struct regcache_ops regcache_rbtree_ops = {
429 .type = REGCACHE_RBTREE,
431 .init = regcache_rbtree_init,
432 .exit = regcache_rbtree_exit,
433 .read = regcache_rbtree_read,
434 .write = regcache_rbtree_write,
435 .sync = regcache_rbtree_sync